Alpha build 2026.11.7

Everything since v2026.11.1.

Optional additions have switches in the game's menus. This is still an alpha, and original-game parity remains in progress. Back up saved zoos before updating.

What's new

Day and night

• Day and night cycle: An optional switch in Game Options > Gameplay adds a twelve-minute day with gradual sunrise and sunset. The cycle pauses with the zoo. Switching it off returns to the original's constant daylight, and the game then looks exactly as before.
• Sun shadows: Guests, staff, animals, trees and scenery cast shadows in their real shape, with arms and legs that follow their movements, leafy tree outlines and the opening under an arch. Buildings cast solid shadows. Shadows turn and grow through the day: short at midday, longer in the evening, fading at sunset and gone at night. They are crisp where they meet the ground and soften towards their tips, more so in the soft light of morning and evening.
• Trees, fences and tanks: Leaves let some light through, so trees cast lighter shadows than buildings. Fences cast their shadow on the ground behind them. Marine tanks cast a simple shadow from their walls, lighter for glass. Flat things such as flowers and grass cast none. Steam, flames and the fountain's water jet do not cast solid shadows.
• Lit buildings: At night, shops, attractions, animal houses, shelters, admission booths, themed buildings and decorations light their windows, signs and lamp fittings rather than the whole building. The restroom signs, the food stands' signs (including the Dinosaur Digs stands), the hot dog and popcorn carts, the vending machines, the rooftop signs of the fish house, dolphin shack, crab house, Mexican café and boat shack, the gift shop's teddy box and balloons, and the Dinosaur Digs gift shop's present all light up. The cinema marquee and arcade roof bulbs stay lit even when nobody is inside.
• Lamps and windows: Streetlights shine down from the lamp head onto the ground and objects nearby, and broken lamps stay dark. Building windows cast light onto the ground outside, and solid objects block it.
• Moving lights: The lighthouse casts a rotating beam from its lantern. The DRT base's red roof beacon and blue landing-pad lights flash as the original's do, and the helicopter shows small markers while its engine runs; its flashing red beacon briefly lights the ground under it. Electric fence shocks and camera flashes briefly light their surroundings. The carousel's bulbs stay steady while it turns.
• Light on tank water: The lighthouse beam and lamps no longer light a marine tank's water like solid ground. Most of the light sinks into the water, and small glints sparkle on the surface where it falls. Light passes through glass tank walls to the water behind them, while solid tank walls catch it as walls do.
• Lit fences: Streetlights and the lighthouse beam now light the fences near them at night.
• Glow around lights: Signs, bulbs, beacons, flames and sparks give off a soft glow into the air around them at night, not only on themselves.
• Fire and water: Torches, campfires, lava and holiday decorations keep their own animated light. Volcanoes and lava pits glow and light the ground all round them. Ponds, fountains, wells, waterfalls and geysers get a gentle night reflection instead of casting light onto the grass.
• Glowing sea life: Green morays respond to blue light. Sea anemones and tree coral have an optional fluorescence effect. They brighten under suitable light rather than glowing in the dark, with a soft glow round them as strong as they are lit.
• Animal colours: Real black markings, such as the orca's, stay black under the lighting.
• Electrified fence beacons: The Dinosaur Digs electrified bars fence's red warning beacons glow at night and cast a small red light on the ground while they flash.
• Night lights for mod items: Buildings, scenery and other items made in the Lab can light up at night. In the Lab's drawing editor, mark a layer as Night light and paint what should glow: windows, bulbs, signs or flames. A night view shows how it will look after dark. A lamp point sets where the light it casts comes from, with its colour, reach and brightness.

Gameplay

• Bulldozer drag: As in the original, drag the bulldozer to clear a rectangle at once. Paths, scenery and fences inside light up red with the total money back, and are cleared when you let go. Buildings are left alone, and walls that would let animals out ask first. A single click now clears on release, as in the original.
• Game speed: The optional Game speed switch in Game Options > Gameplay adds a button beside Pause/Play for normal, 2x and 5x speed. Its arrow count shows the selected speed; it lights up under the pointer and presses in when clicked, and pausing keeps that choice. Turning the switch off restores the original controls and normal speed.
• Time of day: While the day and night cycle or the game speed button is on, a 24-hour clock shows beside the date, in the original's recessed bar, and pauses with the zoo. Turning one of them off keeps the clock while the other is still on; with both off you get the original date display.

Animals

• Babies as often as the original: Animals now pair up as in the original: each grown animal keeps one mate, only that pair has babies, and parents never pair with their own young. Exhibits with several females, or with grown young, no longer have babies far more often than the original, so goals that ask for a baby are as hard as they should be. Some animals, such as pandas, are unhappy for a while when they lose their mate and wait before taking a new one.
• Animals eat their fill: An animal at its food now keeps eating until it is full, as in the original. Before, it took only one bite per meal, so hungry animals could stay hungry and keep walking back to the food over and over.
• Dinosaur eggs: A mother now lays her egg on a free patch of ground a few steps away, as in the original, instead of on top of herself, and eggs hatch at the original moment. Meat-eating dinosaurs and the Plesiosaurus now eat other dinosaurs' eggs, as in the original: the egg breaks and its shell disappears shortly after.
• Newborn animals behave properly: A newborn no longer copies what its mother was doing at the moment it was born, such as sleeping, hunting or sheltering, which could leave babies stuck or acting strangely.
• Young animals act their age: Young animals now use the original's own values for the young: they move at their own pace (a young T. rex walks at half the speed of an adult), cannot jump out of exhibits, attract guests more, play more, and young dinosaurs of some kinds do not test electric fences until they are grown.

Zoo advice

• The original's advisor messages: The message bar now warns, as the original does, when guests comment on sick animals, when protestors demonstrate about poor treatment, and when lots of guests are hungry, thirsty, need a restroom, want a gift or are tired. It also reports when guests complain the zoo is too dirty, and when guests are very happy or unhappy with the zoo. The guest warnings start once more than 10 guests are in the zoo, and each uses the original's thresholds.

Mod Menu

• Choose where mods go: The Mod Menu shows the mods folder and how much room is left on its drive. Folder... picks another folder, from your mods or the repository, and offers to move your mods there: they are copied over while you keep using the menu, and the old copies are removed the next time the game starts. Big mods such as the HD art mods can live on any drive.
• Room for downloads: A download that would not fit on the mods folder's drive is refused before it starts, with how much room it needs.
• Sizes, progress and sorting: Your mods show their size on disk. A part being downloaded shows its progress in the list, and its details show how much has arrived of the total. A Sort button orders your mods by name, size, switched on first or newest, and the repository by name, size or not downloaded first.
• Tidier lists: Sizes sit at the right of each row, and long names are shortened to fit (the full name is in the details). In the repository, a mod that comes in parts has one heading with its parts listed under it. Its heading shows how many parts you have, and its Download next button gets the next part you haven't got.
• Mods you already have: The repository counts a mod as yours when its files are already in your mods folder, even if it didn't come from the repository, instead of offering to download it again.

Updates

• Game updates: The main menu shows beside the version number when the game is checking for updates, downloading or up to date. An available update opens a compact prompt with its download size and progress. A separate update window stays visible while the game installs and reopens.
• Game Options: Mods and Updates now have separate tabs. Updates has the startup-check switch and a Check now button.
• Game Options pages scroll: Every page of Game Options is now one list you scroll with the mouse wheel or its scrollbar, instead of rows split over pages. The Mods page lists all your mods at once, and Display and Graphics have section headings.
• Graphics effects: Game Options > Graphics has a new Effects section: anti-aliasing (FXAA) to smooth jagged edges, bloom, a tilt-shift miniature look, contrast and vibrance sliders, a vignette and film grain. They apply to the zoo only, not the menus, and all are off unless you pick them. They need OpenGL, which the game picks at its next start when one is on.
• Lab updates: The Lab's Check updates button opens a small menu with download progress, size and time remaining. Details shows the installed version, the available version and where it downloads from. Res...

Alpha build 2026.11.1

Everything since v2026.10.30.

Optional additions have switches in the game's menus. This is still an alpha, and original-game parity remains in progress. Back up saved zoos before updating.

What's new

Zoo money

• Original money rules: You can no longer buy something that costs more than your available cash. Objects, animals, staff, fences, paths, gates, tank filters and tank changes are refused with the original's "insufficient funds" message, so a zoo with no money can't keep spending.
• Money warnings: The message bar warns when the zoo is running low on money, when it has run out, and when funding has stopped for all programs.
• Infinite money cheat: Switch on "Cheat: infinite money" at the top of the Mod Menu, or in Game Options > Mods & Updates, to buy anything without your cash going down. Spending still appears in the zoo's finances. It is off by default and takes effect immediately, including in a game in progress.

Bug fixes

Zoo money

• Research and conservation costs: Funding is only paid while a program is actually being researched. A branch with nothing left to research, or with no categories selected, no longer costs money every month.
• Funding with no money: Research, conservation and marketing funding is only paid when the zoo can afford it, as in the original. Funding no longer pushes your cash below zero, and research pauses until money comes in.

Shared saves in the original game

• "Corrupt game save": Shared saves containing benches, bins, show equipment and other buildings open in the original game again instead of being reported as corrupt.
• Trees and plants: Trees and plants added by the game's updates are kept when the zoo is opened in the original.
• Tank walls: Each tank wall style keeps its own look in the original instead of changing to a different style.
• Fences: Fence styles that have no gate no longer show a gap in the original. Fences that can't wear out or break no longer crash the original game.
• Object placement: Objects keep their correct height and identity when the original loads the zoo.
• Tested with every item: Before release, each build saves a zoo containing every animal, staff type, building, fence, tank wall, path and piece of scenery, and checks that the original game loads it correctly.

Marine shows

• Show toys: An animal performing with a toy such as the orca ball no longer shows a second copy of the toy during the trick.
• Stages and platforms: Animals performing on a stage stand on it during the trick instead of beside it.

Tanks and demolition

• Demolishing paths by tanks: The bulldozer now highlights path tiles beside a tank instead of picking the tank's wall, and the red highlight is no longer hidden by the ground around the tank.
• Tank wall highlight: A tank wall picked for demolition glows red where it can be seen, instead of showing a red column hanging below the tank.
• Animals at the tank's edge: Animals swimming at the surface stay inside the tank's walls, including during shows. Leaps, flips, sprays and stage tricks still rise out of the water.

Messages

• Question windows: The Yes and No buttons sit centred under the message, as in the original, and messages keep their own line breaks, such as the refund on its own line when selling.
• Firing staff: You are asked to confirm before firing a worker, with their monthly salary shown, as in the original.
• Message bar: Long messages, such as the insufficient funds warning, wrap onto two lines inside the bar instead of running past its ends.
• Gameplay options: The switches no longer run down over the description box; when there are more than fit, they continue in a second column. Every switch now has a proper name.
• Check for updates row: In copies that can't update themselves, the row reads "Check for updates: not in this copy" on one line instead of turning into an empty scrolling box. The reason is shown in the description.
• Terrain cost with infinite money: The terraform price no longer shows as unaffordable while the infinite money cheat is on.

ZT1 Lab

• Animal maker: In the installed Lab, choosing a new animal's name, type and starting species now opens the editor for painting and building the animal.
• Adding mods: Importing a new mod works in the installed Lab.
• Playing the original: The original game's Continue Saved Game works when the game is started from the Lab.

Alpha build 2026.10.30

Everything since v2026.10.20.

What's new

Marine shows

• Show tanks: Connect an animal's home tank to a show tank, add show equipment and grandstands, then choose the tricks for its performance.
• Show schedules: Set how often a show runs, choose continuous performances, or use Never to stop scheduled shows.
• Marine specialists: An available specialist is assigned automatically when a show is ready to start.
• Show animals: Eligible adults travel to the show through the connecting gate, perform their tricks and return to their home tank afterwards.
• Shared show tanks: Several home tanks can connect to one show tank so animals from different exhibits can use it.
• Trick selection: The show menu checks whether a trick's research, equipment and water-depth requirements are met.
• Show species: Scheduled programs support orcas, dolphins, great white sharks, jellyfish, sea lions and sea otters.
• Grandstands: Guests choose a show and sit in individual seats. Each stand links to the show tank it faces.
• Show admission: Changing a show's ticket price updates the grandstands linked to that show.

Saved games

• Original save import: Load saved zoos from the original Zoo Tycoon, including more of their animals, guests, workers, exhibits and zoo-management information.
• Shared zoo files: The default Save Game option is now Shared zoo (.zoo). One file keeps the full ZT1-Engine zoo and a compatible version that the original game can load.
• Engine-only saves: The save dialog also offers Engine-only save (.zt1save) when you only need to continue in ZT1-Engine.
• Current zoo export: Shared saves include the zoo as it is now, including compatible animals and objects added after loading an original save.
• Custom content: Custom animals, buildings, staff, scenery, filters, food and elevated paths stay in the engine's part of a shared save. The original loads the supported stock content instead.
• Custom paths and fences: Shared saves provide stock equivalents for supported custom paths and boundaries when opened in the original game.
• Animal records: Original imports restore more information about animal identities, age, young animals, eggs, crates, health and needs.
• Guest records: Original imports restore names, appearance, inventory, favourite species, arrival information, needs and thoughts about animals and exhibits.
• Staff records: Original imports restore worker appearance, duties and supported exhibit assignments.
• Research and zoo management: Imports restore research funding and progress, enabled research categories, awards and marketing settings.
• Finance history: More of the original zoo's monthly finances, running totals, cash, date and admission settings are restored.
• Saved show programs: Original trick lists, animal species, frequency and admission settings load into the engine. Compatible programs created in the engine can also be saved for the original.
• Save formats: The dialog changes the file extension to match the selected format. Keep a separate engine copy before resaving in the original, because the original removes engine-only content from its copy.

Animals and habitats

• Animal awareness: Animals account for nearby animals while moving around their exhibit.
• Large marine animals: Swimming and turning take the animal's body size into account near tank walls.
• Marine plants and rocks: Habitat ratings use the individual species' preferences instead of treating every marine decoration as suitable.
• Water requirements: Marine habitat checks account for water depth, cleanliness, salinity and whether the animal needs land.
• Mixed habitats: Animals such as walruses can move between land and water within their enclosure.
• Dinosaur behaviour: Expanded handling for eggs, hatching, feeding, rampaging and capture by the Dinosaur Response Team.
• Animal animations: Improved handling for multi-step actions, turning towards a target, finishing an animation and catching prey.

Mods in the game

• Downloaded mods: Downloads and imports start disabled. Choose which mods to enable after installing them.
• In-game mod switches: Main-menu Enable and Game Options use the same selection. Optional mods can be switched during play.
• Required mods: A mod supplying the current map or placed custom content stays enabled while that content is needed. The menu explains the reason.
• Mod pages: The in-game list uses separate left/right arrow buttons and a Page 1 of N counter.
• Mod pictures: The download menu shows cover images before installation. Lab uploads prepare a cover from the mod's About picture.
• Download sizes: Small files show their size in KB instead of rounding down to 0 MB.
• Custom freeform maps: Maps supplied by enabled mods appear in map selection with their own picture and description. The custommaps option controls this feature.
• Custom names: Mod animals, buildings and staff display their own names in the relevant buy lists and information windows.

ZT1 Lab mod studio

• Mods workspace: Browse a mod's contents by kind, open its artwork and edit its properties in the Inspector. The studio also lists missing parts that need attention.
• New animals: Choose Zoo, Marine or Dinosaur, give the animal a name and select a starting species whose behaviour it will use.
• Existing animals: Create a separate species from an existing animal, then change its appearance, needs, food and behaviour settings.
• Animal needs: Set its carer, food, preferred ground, plants, rocks, shelters and compatible animals, or copy the needs of another species.
• Marine settings: Edit depth requirements, swimming height, wall clearance, salinity and water-cleanliness preferences.
• Dinosaur settings: Edit egg and hatching properties, egg eating, rampaging and fence-breaking behaviour.
• Animal pictures: Create or edit the buy-panel icon, list picture and plaque. A drawn animation frame can be used as the starting picture.
• Item builders: Create new items or customise existing buildings, fences, staff, tank filters, plants, rocks, shelters, enrichment and zoo entrances.
• Staff and guests: Custom staff use an existing job's duties. Guest artwork can replace one of the four existing guest appearances.
• Tank filters: The Inspector exposes cleaning, wear, servicing and upkeep settings for custom filters.
• Paths: Create custom path artwork for all twenty connection shapes.
• Ground textures: Replace the appearance of an existing ground type while keeping that terrain's gameplay properties.
• Animal food: Choose custom food in an animal's Needs page. Its usual keeper or specialist supplies that food.
• Dinosaur egg artwork: Edit the egg, hatching sequence and broken shell separately from the adult animal.
• Remake, Stencil and Blank: Start artwork from an existing picture, trace an outline, or draw from an empty canvas.
• Independent artwork: Own copy separates artwork that was linked to another item so it can be edited independently.
• Animation editor: Edit layers and frames, use a faded view of neighbouring frames as a guide, and preview the animal from different directions.
• Artwork tools: Resize and reshape artwork, recolour selected shades, paint within a stencil, add stripes or fade a pattern across the body.
• Editor controls: Zoom with Ctrl + scroll or the zoom bar. The stencil browser previews animals, people, buildings, plants and fences before selection.
• Building artwork: Edit idle and in-use animations together with the building's static background and default colours.
• PNG imports: Import a single picture, frame strip or directional sprite sheet, fit it to the game's size and preview it before saving.
• OBJ imports: Render a model into game directions. Several supplied poses can be turned into an animation sequence; material and texture files provide its colours.
• Animation links: Reuse an existing pose for selected animal actions while building up a new animal's artwork.
• Game-file editing: Copy an existing game definition into a mod to change values such as an animal's price or a building's capacity. Files already inside a mod can be edited directly.
• Mod pictures: Use your own image, a drawn frame or a Test Zoo picture for the mod's cover.
• Starter kit: A starter mod provides examples of the different kinds of content a mod can contain.

Custom maps, theme packs and Help

• Map editor: Build terrain, water, hills, paths and scenery in the Test Zoo, then save the design into a mod.
• Blank maps: Start at Small, Medium or Large size, or choose your own dimensions. Set the zoo boundary and place its entrance.
• Terrain view: Inspect the map from above while working on its ground layout.
• Theme packs: Select several compatible mods and publish them as one named download with a picture and description.
• Pack conflicts: Conflicting files are reported before creating a pack. The original individual mods remain available for editing.
• Tutorial mods: Wildlife Import Tutorial, Park Workshop Tutorial and Moonstone Habitat Kit are available separately or together as Moonstone Zoo Theme.
• Help tab: A tab beside Mods contains 21 searchable guides, illustrated lessons and nine videos. Press F1 to open it.
• Help topics: Guides cover the Lab workspaces, animal and object imports, habitats, maps, testing, theme packs and publishing or downloading mods.
• Offline Help: Included guides and tutorial media can be viewed without an internet connection. Older recordings are labelled for their earlier interface.
• Lab mod tests: Test Zoo and Play with it use temporary mod selections, keeping an experiment separate from the mods enabled for normal play.

Game windows

• Side-by-side windows: Zoo Status...

Alpha build 2026.10.20

Everything since v2026.10.14.

Every addition beyond the original game is a switch in Game Options. Turned off, the game behaves as the 2001 original did.

What's new

Game Options

• Game Options opens as one window with every setting, and the main menu has it too. Switch: optionswindow (off: the original side panel).
• Display: window, borderless or full screen; window size and full-screen resolution; an FPS limit and V-sync; brightness.
• Interface Size: any size from 0.5x up to the largest the window can show, or Auto. The interface resizes live as you drag.
• Graphics: how zoomed-in art is drawn (FSR, Stylized, Sharp, Smooth or MMPX), and an art sharpness setting.
• Accessibility: colour-blind filters (protanopia, deuteranopia, tritanopia) with a strength setting; cursor size 1x, 2x or 3x; edge scrolling on or off.

Automatic updates

• The installed game and the ZT1 Lab now update themselves. They look 15 seconds after starting and then every 30 minutes.
• Check now: Game Options › Mods & Updates has a Check now button and shows what the updater is doing. The Lab's header button does the same.
• Download first, then ask: a new version is downloaded in the background and checked first. Then the game asks at the main menu, never in the middle of a zoo: Update now, Skip this version or Later. The Lab's header button turns into Restart to update.
• Later installs the update quietly when you next close the game or the Lab.
• Updates are signed: anything that isn't, or doesn't match its signature, is refused.
• The Game Build zip doesn't update itself; get the new version from the releases.

Marine Mania tanks

• Adjust Base goes as far as the original's, up to 12 above the ground: a tank can stand on its rock plinth.
• A tank built over a path clears the path inside it, as the original does.
• Removing a tank puts its sea animals in their aquarium crates straight away, and the food and dung in it go too.
• Removing a tank puts the ground back as it was, instead of leaving a hole. Switch: tankgroundback.
• Fences and tank walls can't be built across a path (along a path's edge is fine). Switch: nofenceonpath.
• Raised walkways (bridges) can't be built over an exhibit or a tank. When a path drag becomes a bridge because the ground is too uneven, the tooltip says so.

Marine Mania animals and staff

• Sea animals swim at the original's heights; surface-only species stay on top.
• Tank ratings and the zookeeper's advice cover depth, cleanliness, salinity and needing land. The info panels name the right carer.
• The marine specialist visits when due, and climbs the tank wall up and down.
• Sick and dying sea animals hold still as in the original. Floor shadows and fight clouds show where the animal is.
• 41 animations that the game's own files name wrongly are now found and shown (the hammerhead's thrash, the marlin's and more). Switch: misnamedart.

Mods

• Mod Menu on the Tutorial & Scenario screen's layout.
• Add a mod... brings in an old Zoo Tycoon download (.ztd), a .zip or a mod folder from your own files. Mods made with the 2001 tools work as they did: their own names, their object files, and big art such as cliff packs.
• Mod repository (the installed game and the ZT1 Lab): browse and download mods from inside the game. Mods are checked for safety (rules and a virus scan) before they're offered. The Game Build zip has the Mod Menu for your own mods only.
• A Mods choice in the buy panels' filter: only what your switched-on mods add or change. Switch: modfilter.
• Mod settings: a mod can have its own options in Game Options.
• Shader mods restyle the art or the whole screen (Game Options › Shaders). The Toon look is now one of these.
• HD art mods carry bigger frames for the zoomed-in map.
• The modders' guide is in docs/MODDING.md.

ZT1 Lab

• Your mods: make a mod, bring one in (drag and drop works), check it against the repository's rules, upload it with your CodeRook account, and see or take down your uploads.
• Experiments can make things: run programs, write files and make mods. The HD art maker is now one of these experiments, so you can copy and change it.
• Sharing (in the header, opt-in): what you find about zoo.exe is shared with other Lab users in the background, and what they find comes to you.
• The game's window in Play is now part of the Lab's window, so it follows when you drag the Lab.
• The original game in Play keeps its own drawing size; clicks and the keyboard reach it.
• New tools: the art kit; the animation maker reads FATZ and shadow frames; memory poke and frame series for the original.

Bug fixes

• Tank walls could be built on top of another tank's water: the cursor aimed at the sunken floor, two tiles off. Walls now go where you point.
• Removing a tank left its sea animals lying on the sand as "escaped".
• Laying a path near a tank or fence didn't show its tiles, so the path looked refused.
• Keeper food (the fish food's swirl, every chow pile) was frozen on its first frame.
• Paths stayed on a new tank's sunken floor under the water.
• Tank heights now use the original's whole units; older saves are converted.
• In the Lab, a function with only a made-up placeholder name now takes the real name someone else shared.
• In the Lab, Build engine no longer fails with LNK1104 in a checkout.
• The walkway self-test's stairs-down drag no longer fails at random.

Alpha build 2026.10.15

Alpha build 2026.10.15

This update replaces the ZT1 Lab installer with a build that includes the previously missing standalone behavior and shared knowledge base connection.

• The Lab uses the bundled ZT1 Engine when a selected source checkout has no engine build of its own.
• The installer offers a standalone mode that does not require selecting a repository checkout.
• The Lab includes the public shared knowledge base endpoint, so users can pull and contribute without configuring a URL. Findings remain provisional until reviewed, and contributions are checked against the supported 2002 Complete Collection build.
• The Lab package includes the Ghidra startup and Steps panel fixes.

The ZT1 Engine installer and game build remain at 2026.10.14 in this release. The game updater feed and their original assets are carried forward unchanged. The Lab installer contains the author's engine and third-party components only; Zoo Tycoon game files and private game data are not included.

Alpha build 2026.10.14

Fixes the game updater's false and unsigned update offers. The engine now accepts only a signed release feed and checks the downloaded installer against its signed size and SHA-512.

Fixes ZT1 Lab's Ghidra setup on a clean machine. The Lab now starts its bundled Ghidra bridge itself and builds a project from the player's installed zoo.exe when needed, with progress shown in the app.

Also fixes the Original Game Steps window resizing inside the Lab and centers the game's main menu button text correctly.

Alpha build 2026.10.13

Alpha build 2026.10.13

A new alpha with real additions. You still need your own copy of Zoo Tycoon — this ships none of the game's files and plays the copy you have installed.

What's new

• Updates. The installed engine now offers each new alpha at the main menu: Update now, Later, or Skip this version. Your saves, mods and settings are kept.
• Game Options work. The original's Sound, Video, Tooltips and Scrolling settings now do what they say, and are remembered.
• An Extras tab in Game Options switches each of the engine's additions on or off. Switched off, it plays exactly as the original.
• Building placement fixed. Buildings snap to whole tiles, as in the original.
• Money as the original counts it. An animal's sale price and the admission price follow the original's rules.
• Marine Mania animals (needs the Complete Collection):
  • Build tanks and adopt marine animals.
  • Put a filter beside each tank: it goes on the tile you click.
  • Marine Specialists work inside the tank, as in the original. They climb in at the gate and dive. Underwater they feed the animals, rake dung, heal and sweep murky water, then climb back out.
  • Maintenance workers repair worn filters.

Still to come: Marine Mania's animal shows (a later alpha), Dinosaur Digs (not ready), scenario goals and events, and loading the original game's .zoo saves.

What to download

Two of these play the game. The third is a tool for looking inside it.

File	What it is
ZT1-Engine-Setup-2026.10.13.exe — 4 MB	The engine. Get this one. An installer with no admin prompt. It reads your Zoo Tycoon where it's installed, and offers each new alpha at the main menu.
ZT1-Game-Build-2026.10.13-win64.zip — 3 MB	The other way to play. A folder that runs on its own, like the first alpha: unzip it anywhere and run start.bat. The first time, it copies your Zoo Tycoon's files in beside the engine — for that it needs Python 3. After that the folder plays by itself, but it doesn't update itself: download the next one when it's out.
ZT1-Lab-Setup-2026.10.13.exe — 570 MB	Not needed to play. The workbench this engine is developed with: it reads your own zoo.exe, shows what each address in it does, records which code runs in which situation, and edits and builds the engine's code. Released beside the game for the first time. Skip it unless that's your thing — details below.

Every download has its .sha256 beside it, so you can check what you got.

The ZT1 Lab, if you want it

It installs the same way, for you alone with no admin prompt, from the Start menu as ZT1 Lab. Everything it needs is inside it — the decompiler (Ghidra) and the Java it runs on, an embeddable Python with the packages its tools use, and its knowledge base — so there is nothing to install first. It reads Zoo Tycoon where it already is, and like the engine it ships none of the game's files.

You can point it at the engine's source if you have it (it will ask), or let it use what it carries.

If Windows warns you

The installers aren't signed yet, so Windows doesn't know them. Click More info, then Run anyway.

Found a bug?

Report it at https://github.com/AlexC1991/zt1-engine/issues. The most useful report says what you did, what the original game does, and what the engine did instead.

Alpha build 2026-10-09

Re-packed 2026-10-12: the download no longer includes copies of Zoo Tycoon's own files (they were in pc-sync/). Nothing changes for players: the engine always read them from your own install.

ZT1-Engine — Alpha Build (2026-10-09)

An open-source engine for Zoo Tycoon 1, for 64-bit Windows.

⚠️ This is a taste of what's being made, not a finished game

This alpha is an early look at work in progress. Please don't judge it as a finished product, and especially not by how much is available right now. A lot is missing, some things are rough, and some things will break. It's here so you can try it, see where it's heading, and help by reporting bugs.

Back up any saves you care about.

📅 New alpha every week

A new alpha build will be released every week. Each one brings fixes and more of the game. Check back for the latest.

You need your own copy of Zoo Tycoon. This download has the engine only, with no Zoo Tycoon art, sound, maps or game files. The first time you run it, it imports them from your own install.

---

Which Zoo Tycoon do I need?

The base Zoo Tycoon game is all you need. You do not need the Complete Collection.

• Base Zoo Tycoon only: works. This alpha is built around the base game, and everything that's ready uses only base-game content. (Tested with just the base game: setup and play work.)
• Complete Collection (with Dinosaur Digs and Marine Mania): also works, and setup imports the expansion files too. But expansion content isn't ready in this alpha (see below), so you don't gain much from it yet.

If you only have the base game, setup shows a warning that Dinosaur Digs and Marine Mania content is missing. That's expected and safe to ignore.

---

Requirements

Windows	10 or 11, 64-bit
Zoo Tycoon 1	The base game is enough (installed or extracted). The Complete Collection works too, but isn't needed
Python 3	Used once, to import your game files. python.org/downloads. Tick "Add python.exe to PATH" when you install it
Visual C++ Redistributable 2015–2022 (x64)	Most PCs already have it. If you get an error about MSVCP140.dll or VCRUNTIME140.dll, install it from aka.ms/vs/17/release/vc_redist.x64.exe
Disk space	About 0.5 GB after setup with the base game, about 1.1 GB with the Complete Collection (the imported game files)

---

Installing and playing

1. Unzip the folder anywhere you like, such as your Desktop or Documents. Avoid Program Files, because Windows blocks writing there.
2. Double-click start.bat.
3. First run only: it checks the usual install folders (Program Files (x86)\Microsoft Games\Zoo Tycoon and similar). If your game isn't in one of them, a window asks you to pick the folder that contains animals.ztd and zoo.exe. The folder is remembered.
4. It imports the game files and sets everything up (about a minute), then the game starts.

After the first run, double-click start.bat again to play. You can also run the game directly with
build\Release\zt1-engine.exe. If you make a shortcut to it, keep "Start in" set to that build\Release folder.

Where your files go

• Saved zoos: Documents\zt1-engine\Saved Games
• Snapshots: Documents\zt1-engine\screenshots

---

What you can try in this alpha

This alpha covers the base Zoo Tycoon game's freeform mode: its animals and items. If you find a bug in any of it, please report it (see Reporting bugs).

• Menus: loading screen, main menu, freeform map selection, credits, the in-game HUD, panels, tooltips and messages
• Base-game animals: adopting and selling, eating, drinking, sleeping, swimming, happiness and exhibit suitability, breeding, illness and old age
• Base-game items: terraforming (raise, lower, smooth, paint), paths, fences and gates, exhibits, scenery, foliage, rocks, shelters and toys, the bulldozer and undo
• Escapes and predators: animals jump, climb or break out; loose meat-eaters chase guests, and keepers dart and crate them
• Guests: needs, tours, donations, thoughts, litter, and running from escaped animals
• Staff: zookeepers, maintenance workers and tour guides; hiring, firing and duties
• Running the zoo: zoo rating, admissions, finances, graphs, research and conservation
• Saving and loading: Save Game, Load Game and Continue Saved Game
• Sound: music, ambience, crowds, guests and animals

Camera: arrow keys or W A S D move · [ / ] zoom · Q / E rotate the view.

---

Known bugs and what's not ready

🐞 Buildings: placement is broken (known bug)

Buildings (shops, restaurants, restrooms and other guest buildings) are in the game, but placing them is broken in this alpha. They may go in the wrong spot or not place properly, and the behaviour isn't the same from one PC to another. It's a known bug being worked on, so you don't need to report it. Please avoid relying on buildings for now. A fix is planned for an upcoming weekly build.

Not in this alpha yet

• Dinosaur Digs and Marine Mania: expansion animals, tanks, shows and dinosaurs are still being built. Their content may show up in menus and buy panels, but it isn't ready to play.
• Scenarios: they open, but their goals and events aren't implemented yet. Stick to freeform.
• Original .zoo saves: can't be loaded yet. The engine uses its own save format, so saves from the original game won't open.
• Linux and macOS: Windows only for now; other platforms are planned.

---

Troubleshooting

"Python was not found"
Install Python 3 from python.org, tick "Add python.exe to PATH", then run start.bat again.

MSVCP140.dll or VCRUNTIME140.dll is missing
Install the Visual C++ Redistributable (x64).

Setup warns that Dinosaur Digs / Marine Mania content is missing
That's normal if you only have the base game. Ignore it; this alpha doesn't need the expansions.

It used the wrong Zoo Tycoon folder, or I want to import from a different one
The files are only imported once, so start again from scratch. Open a Command Prompt in the unzipped folder and run:

start.bat --clean
set ZT1_SOURCE_DIR=D:\Games\Zoo Tycoon
start.bat

Replace the path with the folder that has animals.ztd and zoo.exe in it.

Sound is slow, scratchy or muffled
The engine uses DirectSound by default, because Windows' newer WASAPI audio sounded wrong on some PCs. To try a different audio driver, open a Command Prompt in the build\Release folder and run:

set SDL_AUDIODRIVER=wasapi
zt1-engine.exe

This only affects that one launch. It doesn't change anything else on your PC.

Something went wrong during setup
Run start.bat --clean, then start.bat again for a fresh setup. --clean removes the imported game files (they're imported again on the next run) but keeps the engine. Your saved zoos in Documents are not touched.

start.bat options

Command	What it does
start.bat	Set up (first time) and play
start.bat --setup	Only import the game files, then stop
start.bat --clean	Remove the imported game files and settings for a fresh setup (keeps the engine)

To import from a particular folder, set ZT1_SOURCE_DIR=<folder> before running start.bat.

---

Reporting bugs

This alpha exists to find problems, so if you find a bug, please report it. Every report helps the weekly builds get better. The most useful report shows where the engine differs from the original game:

1. What you did
2. What the original Zoo Tycoon does
3. What the engine did instead

Add a screenshot or your saved zoo (from Documents\zt1-engine\Saved Games) if you can. Saying which alpha build (the date in the folder name) you were playing helps too.

Report issues at https://github.com/AlexC1991/zt1-engine/issues.

Building placement is already known (see Known bugs), so there's no need to report it.

---

Legal and credits

Zoo Tycoon is © Microsoft Corporation, developed by Blue Fang Games. This project is not affiliated with or endorsed by Microsoft or Blue Fang Games. It ships none of the original game's files. You need your own legitimately obtained copy.

ZT1-Engine is free and open source under the MIT License (see LICENSE.txt), © 2025 Wouter (sharkwouter) Wijsman and contributors.
Source code: https://github.com/AlexC1991/zt1-engine

It uses these open-source libraries: SDL2, SDL2_image, SDL2_mixer, SDL2_ttf, FreeType, libzip, zlib and pe-resource-loader. Portions of this software are copyright © The FreeType Project (www.freetype.org). All rights reserved.

The icon uses a photo by Magda Ehlers from Pexels.

This software is provided "as is", without warranty of any kind. It's an alpha: use it at your own risk.